The present invention relates to an organopolysiloxane composition or, more particularly, to a composition having pasty consistency suitable for the base of various cosmetic and medicinal preparations such as cosmetic creams, hair dressings, ointments and the like compounded with a cyclic organopolysiloxane compound having volatilizability as the principal ingredient.
It is well known that a silicone oil or an organopolysiloxane fluid is admixed with a pasty material used as the base of various cosmetic and medicinal preparations such as creams, hair dressings, ointments and the like. The silicone oil in these applications is used merely as an additive in a relatively small amount. Namely, silicone oils are rarely used as a principle ingredient in such a pasty composition. When a silicone oil-based pasty composition is desired, it is usual that the silicone oil is compounded with a considerably large amount of an inorganic filler as a thickening agent such as finely divided silica powder optionally rendered hydrophobic by a surface treatment, bentonite and the like to impart a pasty consistency. The silicone oil compounded with such a thickening agent still should have a relatively high viscosity of, for example, at least 100 centistokes at 25.degree. C. so that the pasty composition prepared from such a viscous silicone oil and a thickening agent is sometimes not acceptable by the users of the cosmetic preparations or the patients using the medicinal preparations because of the heavy spreadability on the human skin in application and lack of refreshingness due to the lasting stickiness as a consequence of the absence of any volatile constituents in the preparations.
Use of a low-viscosity cyclic organopolysiloxane has been proposed in place of the high-viscosity silicone oils in the above mentioned applications (see, for example, Japanese Patent Kokai No. 61-271206, 61-246112 and 62-12710). Since these cyclic organopolysiloxanes have a low viscosity, the composition composed of such a cyclic organopolysiloxane and a thickening agent alone can hardly be imparted with a pasty consistency. Alternatively, a proposal is made to use a silicone resin having three-dimensional siloxane linkages in place of the above mentioned inorganic thickening agents for the cyclic organopolysiloxanes to impart a pasty consistency. This method is also not satisfactory because silicone resins have relatively poor thickening effects for the cyclic organopolysiloxanes unless the compounded amount thereof is quite large with a consequent decrease in the relative content of the cyclic organopolysiloxane so that no smooth and light spreadability of the preparation on the skin and refreshingness can be obtained.
Investigations have of course been undertaken for the use of various thickening agents conventionally used in cosmetic and medicinal preparations including cellulose derivatives such as nitrocellulose, ethyl cellulose and the like and fatty acid esters of polysaccharides. These conventional thickening agents, however, cannot be used for cyclic organopolysiloxanes because they are poorly compatible with organopolysiloxanes not to be dissolved therein though not absolutely without swellability.